Ive looked everywhere and I can't find it so I have a 05 pre runner and im about to drive 600+ miles from Mississippi to Texas with roughly 4000 lbs enclosed trailer. when I put it in "d" i dosen't run as low as it does in overdrive but when i put it in 4 it runs up there. so my question is, is it ok to run in "d" when going pretty much across the flattest land i have ever drove on ? I know i get roughly 8 mpg when in 4 and ouch that junk hurts but the truck gets lighter the father i drive cause my wallet will be empty by the time I get there. Any comments

I would drive in 4th, not in OD. I pulled a trailer across country and as wushaw stated your transmission will be hunting way too much, your revs will be high and our wallet will be lighter too, sorry but that's how's it going to be. Maybe you could mount a mast and hope for a nice tail wind.

I tow a 4,000 lb Pop-up every other weekend, in Texas (pretty flat). Been doing it for a year in 5th gear. If you can drive it to where it is not shifting in & out of 5 (w/TCC engaged), I think it is ok. If you don't feel comfortable, drive in 4. DO NOT USE CRUISE CONTROL if you are in 5 though... I get 13-14 in 4th gear, 16-17 in 5th.

17k miles on a 07 truck, I have had the truck one year. TGFT (Thank God For Tacomas)